Known molten molding material dispensers, also called valves or nozzles, include an outlet body defining an outlet and an outlet cover (such as a stem, a pin, a disk or a ball) that may be moved or displaced relative to the outlet so as to disable or enable flow of a molten molding material from the outlet. Such dispensers are used in molding machines, hot runner assemblies and/or molding assemblies. Movement of the outlet cover may be realized by having a mechanical actuation structure contact, urge and move the outlet cover. The mechanical actuation structure may include a spring, an air actuator, a hydraulic actuator, etc, either individually or in suitable combination. Such mechanical actuation structures may experience a short life span due to mechanical wear, may corrode due to exposure to the molten molding material, may undergo frequent maintenance and/or may experience inadvertent failure during molding machine operation.
U.S. Pat. No. 4,427,361 discloses a spring-actuated dispenser. Known spring-actuated dispensers may potentially experience difficulty shutting off the flow of molten molding material due to premature mechanical breakdown of the mechanical actuation structure. The spring may inadvertently restrict flow of molten molding material, and may also cause contamination of the molten molding material in the form of material hang-ups.
U.S. Pat. Nos. 6,287,107, 6,343,935 and 6,228,309 disclose hydraulic-, air- and electronic-actuated dispensers. Known air- and hydraulic-actuated dispensers may include mechanical actuation components that are subject to wear and thereby may inadvertently leak molten molding material from the dispenser. This may undesirably hamper dispensing operation, require frequent maintenance, and/or lead to loss of molten molding material. It is known that 75% of the molding machine operating cost is attributed to the cost of the molding material and any wasted molding material represents an unrecoverable cost.
U.S. Pat. Nos. 4,437,488 and 5,364,252 disclose a dual-actuated molten plastic dispenser that combines mechanical-actuation components with magnetic-actuation components. This dispenser requires both mechanical-actuation components and magnetic-actuation components in operable combination. When the mechanical actuation components fail to operate, this dispenser may fail to operate altogether as a unit because the mechanical actuation components are subject to premature wear.
Therefore, a solution is desired which addresses, at least in part, the above-mentioned shortcomings and/or other potential shortcomings.